Among components added to skin care products, ultraviolet light absorbers are divided into a UV-A absorber and a medium-wave ultraviolet light (UV-B: 280 to 320 nm) absorber.
Recently, it has been found that UV-A enhances pigmentation such as blemish or freckle and dermatopathy due to UV-B, and the development of a UV-A absorber has been regarded as important. Examples of the currently known UV-A absorber include benzophenone derivatives, benzotriazole derivatives, dibenzoylmethane derivatives (4-(tert-butyl)-4′-methoxydibenzoylmethane and the like) (Japanese Published Examined Patent Application No.86-16258) and the like. Meanwhile, oils currently used for cosmetics have a problem that they are poor in solubility of the UV-A absorber and cannot make cosmetics contain a sufficient amount of the UV-A absorber.
As oils for cosmetics excellent in solubility of a UV-A absorber, esters of a carboxylic acid or dibasic acid having from 4 to 18 carbon atoms and an alcohol having from 2 to 18 carbon atoms which have a total carbon number of 12 or more (isopropylmyristate, cetyloctanoate, 2-ethylhexylpalmitate, 2-ethylhexyl succinate and the like) are disclosed (Japanese Published Unexamined Patent Application No.97-263524). However, the development of oils for cosmetics having better solubility of a UV-A absorber has been in demand.
Moreover, cosmetics using 2-ethylhexyl succinate and the like have problems in that they do not show good emulsifiability based on phospholipid, sorbitan-type surfactants and the like, that they are insufficient in moist feeling, smoothness and the like when used as creams or the like and that they are insufficient in combing, moist feeling and the like when used as hair care products. Thus, they are unsatisfactory in practical use.